Apparatus for and method of stretching,sealing and removing the tab from packages



Oct. 14, 1969 J. A. BONUCHI ETAL 3.471,990

APPARATUS FOR AND METHOD OF STRETCHING, SEALING AND REMOVING THE TAB FROM PACKAGES .2 Sheets-Sheet 1 Filed Jan. 5, 1967 INVENTORS damea 4. flaw/ch floxm/a L. 15 4/75 I I Q" I Y ATTOR 5 O 1969 J. A. BONUCHI ETAL 3,471,990

I APPARATUS FOR AND METHOD OF STRETCHING, SEALING AND REMOVING THE TAB FROM PACKAGES Filed Jan. 5, 1967 2 Sheets-Sheet 2 INVENTOR5 James A flow/ch flo/m/a L. Eva/7.5

Ill/1 I ATTOR.

United States Patent US. Cl. 53-22 8 Claims ABSTRACT OF THE DISCLOSURE Packaging apparatus having heating structure for producing a line of seal arross the initially open end of a polyethylene bag containing poultry products. The apparatus is provided with a sponge which is clampable against the package prior to scaling the same for expelling air therefrom to produce a tight package. The apparatus is also provided with a pair of opposed rollers receiving the initially open end of the bag therebetween for pulling the end outwardly away from the remainder of the bag to stretch the latter over the product in the bag and thereafter remove excess material which extends outwardly beyond the line of seal.

This invention relates to packaging apparatus for heat sealing the initially open end of a bag of heat-scalable material containing a product to be packaged, and particularly relates to mechanism for producing a tight, compact and attractive package.

Bags of heat-scalable material such as polyethylene have been utilized in the past for packaging products and particularly food products such as poultry. After the product is placed in the bag, heat is applied across the initially open end of the bag to seal the latter by fusing the layers of the same together. In order to produce an attractive and practical package it has been found that the bag should be stretched tightly against the product before the bag is sealed. Furthermore, the seal should be made at a location as close to the product as possible so that the resultant package will retain its compactness. Necessarily, the initial bags are larger than required and thus, after the seal is effected, a tab of excess material remains and extends outwardly from the seal.

Therefore, it is the promary object of the instant instant invention to provide mechanism for use in conjunction with the heating structure of such apparatus wherein the bag is pulled tightly against the product prior to the time the bag is sealed and thereafter, the tab of excess material is automatically removed. In this respect, it is a very important aim of the invention to provide such mechanism wherein the initially open end of the bag is continually pulled outwardly prior to scaling, during sealing and after sealing, to the end that the packaging operation is rendered simple and, therefore, efficient.

Another very important object of the instant invention is to provide a compressor for such apparatus to squeeze the bag against the product prior to scaling the bag whereby excess air is forced out of the package and the latter is therefore rendered more compact.

Another important object of the instant invention is to provide such heating structure and pulling mechanisms which work together as a unit to pull the bag tight, seal the same at a zone of seal adjacent the final package, and thereafter pull the tab of excess material and separate the same from the package at the zone of seal whereby a tightly packed, attractive package is produced efiiciently and economically.

In the drawings:

FIGURE 1 is a fragmentary, elevational view illustratice ing the front end of a portion of a packaging machine embodying the concepts and principles of the instant invention;

FIG. 2 is an elevational, cross-sectional view taken along line 22 of FIG. 1;

FIG. 3 is a view similar to FIG. 2 after the machine has been operated and has moved through a portion of its cycle, the prime movers associated with the machine having been illustrated schematically;

FIG. 4 is a cross-sectional view taken along line 44 of FIG. 2;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 1;

FIG. 6 is an enlarged, detail, cross-sectional view taken along line 6-6 of FIG. 4; and

FIG. 7 is an enlarged, cross-sectional detail view taken along line 7-7 of FIG. 4.

A packaging machine embodying the principles and concepts of the instant invention is fragmentarily illustrated in FIGS. 1, 2 and 3 and is broadly designated by the numeral 10. Machine 10 is adapted for packaging products, and particularly food products such as poultry, within a bag 12 of heat-sealable material such as polyethylene or the like. The product within bag 12 is not illustrated in detail; however, it will be understood by those skilled in the art that the product rests in a dishshaped tray 14 of paper-like material as illustrated by dashed lines in FIG. 3. Bag 12 has an initially open end 16 including a pair of overlapping marginal layers 18 which present a tab of excess material 20 after the bag has been sealed at a zone of seal 22.

Machine 10 is provided with a shiftable support 24 having a horizontally extending bar 26 rigidly connected to a pair of vertical legs 28 by fasteners 30. Legs 28 extend downwardly from bar 26 through table 32 of machine 10 and are interconnected beneath table 32 by a yoke 34 shown schematically in FIG. 3. The piston rod 36 of a piston and cylinder assembly 38 (also shown schematically in FIG. 3 is connected with yoke 34 and is extendible and retractable to raise and lower support 24.

Heating structure 40 is provided for sealing bag 12 at zone 22. Structure 40 includes an elongated, upper clamping member 42. Member 42 is provided with an aperture 44 aligned with the apertures 46 within a pair of spaced flanges 48 extending downwardly from bar 26-. Nut and bolt means 50 extend through apertures 44 and 46 to permit swinging of member 42 relative to support 24. A guided spring 52 is disposed on each side of means 50 for yieldably maintaining member 42 in a horizontal disposition.

Structure 40 also includes an elongated, lower member 54 extending substantially parallel to member 42 in normally spaced, opposed relationship to the latter. Members 42 and 54 are provided with respective, opposed clamping surfaces 56 and 58. A Teflon coated metallic wire 69 extends between spaced tightening means 62 at opposite ends of member 42 to present a knife edge extending longitudinally across surface 56 thereof, and adjustment means 64 are provided at opposite ends of member 42 for adjusting the position of wire 60 on surface 56.

Viewing FIG. 6, it can be seen that tightening means 62 comprises a shaft 66 rotatable in a vertical aperture 68 in member 42 and has a knurled head 70 at one end thereof, and an aperture 72 at the other end receiving wire 60. After shaft 66 has been rotated by the application of finger pressure to head 70, sufiiciently far to tighten wire 60, lock screw 74 is tightened against shaft 66 to preclude further rotation of the same relative to member 42.

Viewing FIG. 7, it can be seen that adjustment means 64 includes a threaded shank 76 having an elongated bridge member 78 extending laterally and downwardly therefrom. Bridge 78 receives wire 60 in a notch 80 at the lower end of bridge 78. A knurled nut 82 is provided at opposite ends of shank 76 and on each side of member 42 and it can be seen that, by loosening one nut 82 and tightening the other, bridge 78 will be moved laterally of member 42 through slot 84.

Machine 10 is provided with mechanism in the nature of opposed rollers 86 and 88 for pulling outwardly on end 16 of bag 12 to tighten the latter prior to sealing and to remove tab 20 after the bag has been sealed. Roller 88 is mounted adjacent member 54 between bearing structures 90, and a belt 92 is trained around roller 88 and the drive wheel 94 of a prime mover 96. Upon actuation of prime mover 96, roller 88 is caused to rotate in the direction indicated by the arrow in FIG. 3.

Opposite ends of the shaft 98 of roller 86 are rotatably received in respective, elongated supports 100 extending downwardly from support brackets 102 mounted on bar 26. In this respect, it is to be noted that supports 100 extend through aligned openings in the horizontal flanges 104 of brackets 102, and an annular enlargement 106 is provided for each support 100 to limit downward movement of the same relative to bracket 102. A spring 108 is provided for each support 100 respectively for yieldably biasing roller 86 downwardly toward roller 88. It is to be noted that its initial position (FIG. 2), roller 86 is disposed in closer relationship to roller 88 than is member 42 with respect to member 54.

A brace 110 extends rearwardly from bar 26 and mounts a resilient pad in the nature of a semirigid block 112 of deformable, foam-like material disposed in overlying relationship with respect to bag 12. It can be seen, viewing FIGS. 2 and 3, that upon retraction of rod 36, roller 86, member 42, and block 112 move downwardly as a unit toward roller 88, member 54 and bag 12, respectively. It is to be appreciated that member 54 is provided with an impulse heating strip 114 of the type familiar to those skilled in the art which is actuatable after layers 18 have been clamped between members 42 and 54, to heat layers 18 sufiiciently to fuse the same together at Zone 22.

As support 24 begins its descent during the retraction of rod 36, block 112 contacts bag 12 and compresses the same tightly against the product therewithin. The deformability of the block 112 permits the same to be deformed into the exact shape of the product in the bag resulting in a contoured tight engagement therebetween and thus, substantially all of the excess air within bag 12 is forced out through end 16 which has not yet been sealed. In the meantime, roller 86 moves toward roller 88 to clamp layers 18 therebetween and the rotation of roller 88 causes end 16 to be frictionally pulled outwardly and away from the product in bag 12 to thereby tighten the latter. In this respect, it is to be appreciated that the action of rollers 86 and 88, and the action of block 112, are supplemental, the block 112 being primarily for compresing excess air out of bag 12 while the rollers 88 and 86 stretch the film of the bag tightly over the product therewithin. It is to be noted that rollers 86 and 88 are provided with circumferentially extending grooves 116 to permit air to escape from bag 12 after rollers 86 and 88 have clamped layers 18 therebetween.

After bag 12 has been compressed by block 112 and stretched by rollers 88 and 86, surfaces 56 and 58 of members 42 and 54 move into clamping relationship with respect to zone 22 and strip 114 is actuated to seal bag 12 at zone 22. In this respect, it is to be noted that roller 86 has been moved upwardly with respect to bracket 102 against the bias of springs 108 and, therefore, although roller 86 moves into frictional engagement with layers 18 before the same are clamped between members 42 and 54, the yieldable support for roller 86 provided by springs 108, permits roller 86 to move upwardly while the same is maintained in tight frictional engagement with layers 18.

Manifestly, the action of heating strip 114, in effecting the sealing of bag 12 at zone 22, weakens bag 12 at zone 22 and thus, rollers 88 and 86, because they are still tightly frictionally engaged with tab 20, pull the latter outwardly and away from zone 22 and thus separate the tab from the bag at zone 22. Rollers 88 and 86 pull layers 18 outwardly and away from the product within bag 12 prior to the sealing of the latter to thereby stretch the bag over the product therewithin. Rollers 88 and 86 continue to pull outwardly on layers 18 during the sealing operation operation and thereafter to positively separate tab 20 from bag 12 and thereby provide a neat, compact, attractive package.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent 1s:

1. In a machine for packaging a product contained in a bag of heat-sealable material having a pair of overlapping marginal layers, presenting an initially open end.

heating structure including a pair of normally spaced,

opposed members shiftable relatively toward one another and into clamping relationship with respect to said layers, said structure having heating means operable after said members are clamped against said layers for sealing the latter together to present a tab of excess material extending outwardly beyond the zone of seal; and

mechanism for grasping said layers and pulling the same outwardly and away from the product in the bag prior to clamping, during sealing and after sealing to stretch the bag over the product and to separate the tab from the bag at said zone,

said machine including a compressor having a resilient pad movable against said bag prior to said clamping for pushing air out of the bag and holding the latter tight against the product therein during operation of said heating means.

2. The invention of claim 1, wherein said pad comprises a semirigid block of plastic substance deformable upon contact with said bag and the product therein into contoured tight engagement therewith.

3. In a method for packaging a product contained in a bag of heat-scalable material having a pair of overlapping marginal layers presenting an initially open end, the steps of:

compressing the bag against the product therein to squeeze air out of the bag;

clamping said layers together at a zone of seal and heating the layers sufficiently at said zone to cause the material of the layers to fuse, presenting a tab of excess material extending outwardly from said zone; and

continuously pulling said layers outwardly and away from the product in the bag during compression, prior to clamping, during heating and after sealing to stretch the bag over the product and to separate the tab from the bag at said zone.

4. In a machine for packaging a product contained in a bag of heat-sealable material having a pair of overlapping marginal layers, presenting an initially open end,

heating structure including a pair of normally spaced,

opposed members shiftable relatively toward one another and into clamping relationship with respect to said layers, said structure having heating means operable after said members are clamped against said layers for sealing the latter together to present a tab of excess material extending outwardly beyond the zone of seal;

mechanism for grasping said layers and pulling the same outwardly and away from the product in the bag prior to clamping, during sealing and after sealing to stretch the bag over the product and to separate the tab from the bag at said zone,

said mechanism including a pair of normally spaced,

opposed rollers receiving said layers therebetween, said rollers being shiftable relatively toward one another and into frictional engagement with said layers, there being provided power means coupled with one of the rollers for rotating the latter in a direction to frictionally pull said layers away from the product in the bag; and

a shiftable support carrying a first of said rollers and a first of said members for movement therewith as a unit toward and away from the remaining roller and member, I

said members being elongated and having respective,

opposed, generally parallel clamping surfaces,

said first member being swingably mounted on said support for adjusting the relative dispositions of said surfaces during said clamping.

5. In a machine for packaging a product contained in a bag of heat-sealable material having a pair of overlapping marginal layers, presenting an initially open end,

a support for the bag and its contained product;

structure movable toward the bag for clamping the latter against the support forsqueezing air out of the bag through said open end;

mechanism for grasping said layers to pull the bag taut around the product as the air is squeezed from the bag; and

heating means for sealing said layers together between said structure and said mechanism after the air has been squeezed from the bag,

said mechanism continuing to pull said layers during and after sealing whereby to dispose of excess bag material extending outward-1y beyond the seal.

6. The invention of claim 5,

said structure including a pad of resilient material,

permitting said mechanism to stretch the bag onto the product while air is squeezed from the bag.

7. The invention of claim 5,

said mechanism including a pair of rollers movable relatively into and out of grasping relationship to said layers,

said heating means including a pair of elements movable relatively into and out of clamping relationship to said layers; and

actuating means common to said structure, mechanism,

and heating means.

8. The invention of claim 7,

one of the rollers being yieldable relative to the actuating means after the rollers grasp said layers, permitting continued relative movement of said elements.

References Cited UNITED STATES PATENTS 3,377,772 4/1968 Lyon et a1. 53372 X 2,796,913 6/ 1957 Fener et a1.

3,011,295 12/1961 'Brugger 53-372 2,496,609 2/1950 Van Antwerpen 53--373 2,877,615 3/1959 Foster 53-112 25 ZIHERON E. CONDON, Primary Examiner HORACE M. CULVER, Assistant Examiner US. Cl. X.R. 

